Due to the increasing energy demands, offshore oil and gas production is moving into deeper waters. For ensuring an efficient and secure production, processing facilities are being installed at the ocean floor. Such subsea installations can comprise a range of components, including pumps, compressors and the like as well as a power grid for operating them. The power grid may for example comprise a subsea transformer, subsea switchgear and subsea variable speed drives. The components of the subsea installation need to be protected from the surrounding sea water, in which pressures of 300 bar or more can prevail (at installation depths of 3.000 m or more).
Components of such subsea installation can comprise electronic equipment that can be monitored and/or controlled from a topside installation, such as a topside control system which may be located on a fixed or floating vessel, in particular on a ship or a platform, or may be based onshore. The subsea installation can for example comprise one or more subsea control modules (SCM) which may receive commands from the topside installation or which may transmit information to the topside installation, which may communicate with each other or which may interface a sensor. In other installations, data communication is to be performed with sensors of a valve tree or other subsea equipment.
In such systems, communication links may for example be required between the sensors and a subsea control modules or a topside installation, between subsea control modules and a topside installation, or between different subsea control modules. Communication can be implemented by way of a network communication, such as Ethernet. Although such type of communication link can achieve relatively high bandwidth, e.g. 10 Mbps, 100 Mbps or even 1 Gbps, such types of communication links are limited in their physical length. As an example, Ethernet based on a twisted copper wire pair has a limited length of about 100 m according to Ethernet standards. Enhanced solutions may achieve distances exceeding 150 meters length of the communication link. In general, communication using such type of technology is thus limited to subsea control modules of the same valve tree. A communication between different valve trees is usually not possible, each installation requiring their own link to a topside installation via an umbilical or the like.
To overcome this problem, the use of fiber optic transmission is known. Yet fiber optic transmission cables also require respective optical connectors. In particular wet-mateable optical connectors that can be connected and disconnected in the subsea environment are complex and expensive.
To decrease the complexity and increase the reliability, a solution is proposed in the document EP 2713191 A1. An electrical connector is provided that converts an optical signal from a fiber optic transmission line into an electrical signal to allow the establishing of an electrical connection with a wet-mateable electrical connector for data transmission.
Although such solution provides significant advantages, the resulting connector is relatively large and bulky. This can make the connector difficult to handle for a remotely operated vehicle (ROV). Further, significant forces act on the connector and its components due to the increased weight of the connector and from the cable connected thereto. This can be detrimental to such connectors. Also, the structure to which the connector is connected may generate vibrations, for example a subsea pump or a subsea compressor. Such vibrations affect all parts of the connector, and also the conversion part including the optical components. Further, such vibrations in combination with the added weight can cause damage to the connector or some of its components.